Bicycle rear derailleur guard

ABSTRACT

A bicycle rear derailleur guard assembly for use with a bicycle having a derailleur mounted to a frame of the bicycle by a derailleur mounting bolt. The derailleur guard assembly preferably includes a body supportable by an axle assembly of the bicycle. The body is configured to extend from an axis of the axle assembly to a space adjacent the mounting bolt of the derailleur and defines an inner surface facing the frame when the guard assembly is mounted to the bicycle. A support is configured to support the derailleur when the guard assembly is mounted to the bicycle and, in at least one arrangement, the body is positioned outwardly of the derailleur mounting bolt within the space adjacent the mounting bolt.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to bicycles and, more particularly, to a rear derailleur guard assembly for a bicycle.

2. Description of the Related Art

Bicycles, especially mountain bikes, or bicycles intended for off road use, are often equipped with a multi-speed drive train to provide a variety of available gear ratios to a rider of the bicycle. Due to the wide variety of terrain upon which a mountain bike may be ridden, in comparison to other types of bicycles, a relatively large range of gear ratios are often provided. For example, a very low gear ratio is beneficial when climbing a steep hill, while a much higher gear ratio permits the cyclist to travel at high speeds on flat ground or when going down a hill.

A chain and sprocket arrangement is a common type of drive train provided on current bicycles. A typical chain and sprocket arrangement includes a continuous drive chain interconnecting a selected one of a plurality of sprockets mounted to a pedal crank of the bicycle with a selected one of a plurality of rear sprockets drivingly connected to a rear wheel of the bicycle. Front and rear derailleurs are provided to move the drive chain to a selected one of the plurality of front and rear sprockets, respectively. Front and rear shifters control the front and rear derailleurs, respectively, and permit the rider of the bicycle to choose between the available gear ratios provided by the combination of front and rear sprockets.

As described above, the rear derailleur is configured to move the drive chain among the plurality of rear sprockets, or cogs. The rear derailleur typically includes a fixed portion mounted relative to the bicycle frame and a moveable portion, or cage. A pair of small sprockets, or pulleys, are supported at upper and lower ends of the cage and opposing sides of the pulleys engage the drive chain. As described, the rear shifter controls the rear derailleur to move the cage into alignment with a selected one of the plurality of rear cogs and the pulleys urge the drive chain into engagement with the selected cog.

In addition to moving the drive chain between cogs, the rear derailleur also operates to absorb slack in the drive chain, which increases with smaller gear ratios and decreases with larger gear ratios. The amount of slack taken up by the rear derailleur is influenced in part by the distance between the pair of pulleys and, thus, by the length of the derailleur cage. Accordingly, with the relatively large difference between the largest gear ratio and the smallest gear ratio found on most mountain bikes, the rear derailleur is often equipped with a relatively long derailleur cage.

The difference between the smallest and the largest gear ratios for a mountain bike is typically greater than the difference between the smallest and largest ratios for a bicycle intended primarily for use on the road. Accordingly, the derailleur cage is typically longer on a mountain bike than on a road bike. Thus, a mountain bike rear derailleur is much more likely to be damaged as a result of being struck by objects encountered while riding, such as rocks or sticks, than the derailleur cage of a road bike, due to the additional length of the derailleur cage.

The rear derailleur is typically mounted to a tab, or derailleur hanger, which extends from the bicycle frame to a position below the hub axis of the rear wheel. Typically, a derailleur mounting bolt supports the rear derailleur from the bicycle frame in a cantilevered arrangement. That is, the mounting bolt includes a threaded end, which engages a threaded aperture of the derailleur hanger, and a shaft portion, which extends outwardly from the derailleur hanger. The rear derailleur is supported on the shaft portion of the mounting bolt. Such an arrangement is highly susceptible to damage as a result of objects striking the derailleur cage. For example, the derailleur hanger may be bent, which may cause a misalignment between the derailleur cage and the plurality of cogs, thereby causing a reduction in shifting performance. In other cases, the derailleur mounting bolt may be broken, which may render the bicycle unridable.

SUMMARY OF THE INVENTION

Accordingly, a need exists for a derailleur guard that is configured for use in the environment of an off-road bicycle, or mountain bike. Desirably, such a derailleur guard provides support to an outward end of the derailleur to inhibit damage to either of the derailleur hanger or derailleur mounting bolt. In one arrangement, a preferred derailleur guard does not interfere with moving portions of the derailleur, which may swing forwardly as the bicycle traverses rough terrain. Another embodiment of the derailleur guard may be adjustable so as to be adaptable to a variety of frames, which may have varying dimensions of the derailleur hanger relative to the mounting site of the derailleur guard, such as a hub axis, for example.

A preferred embodiment is a bicycle rear derailleur guard assembly for use with a bicycle having a derailleur mounted to a frame of the bicycle by a derailleur mounting bolt defining a tool cavity. The derailleur guard assembly includes a body supportable by an axle assembly of the bicycle. The body is configured to extend from an axis of the axle assembly to a space adjacent the derailleur mounting bolt and defines an inner surface facing the frame when the derailleur guard assembly is mounted to the bicycle. A support extends from the inner surface and is configured to engage the tool cavity of the derailleur mounting bolt when the derailleur guard assembly is mounted to the bicycle. The support and the derailleur mounting bolt cooperate to create a support beam for the derailleur. The support beam preferably is rigidly supported by the frame at a first end and rigidly supported by the body at a second end.

A preferred embodiment is a bicycle rear derailleur guard assembly for use with a bicycle having a derailleur mounted to a frame of the bicycle by a derailleur mounting bolt which preferably defines a tool cavity. The derailleur guard assembly includes a body supportable relative to an axis of an axle assembly of the bicycle. The body is configured to extend to a space adjacent the derailleur mounting bolt and define an inner surface facing the frame when the derailleur guard assembly is mounted to the bicycle. A support extends from the inner surface and is at least indirectly supported by the derailleur mounting bolt to support the derailleur when the derailleur guard assembly is mounted to the bicycle. Preferably, the support is configured to contact the tool cavity. A linear distance between the support and the axis of the axle assembly when said derailleur guard is mounted on the bicycle is adjustable.

A preferred embodiment is a bicycle rear derailleur guard assembly for use with a bicycle having a derailleur mounted to a frame of the bicycle by a derailleur mounting bolt. The derailleur guard assembly includes a body supportable by an axle assembly of the bicycle. The body is configured to extend from an axis of the axle assembly to a space adjacent the mounting bolt of the derailleur and defining an inner surface facing the frame when the guard assembly is mounted to the bicycle. A support is held by the body and is configured to support the derailleur when the guard assembly is mounted to the bicycle. The body is positioned outwardly of the derailleur mounting bolt within the space adjacent the mounting bolt.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the present invention are described in greater detail below with reference to drawings of preferred embodiments, that are intended to illustrate, but not to limit the present invention. The drawings contain 11 figures.

FIG. 1 is a side elevational view of an off-road bicycle, or mountain bike, incorporating a rear derailleur guard assembly having certain features, aspects and advantages of the present invention.

FIG. 2 is an enlarged, perspective view of a portion of the bicycle of FIG. 1, illustrating the derailleur guard assembly in greater detail.

FIG. 3 is an exploded, perspective view of the portion of the bicycle and derailleur guard assembly of FIG. 2.

FIG. 4 is a cross-sectional view of a portion of the bicycle frame and derailleur guard assembly taken along the line 4—4 of FIG. 2.

FIG. 5 is an enlarged cross-sectional view of a support member including a hexagonal shaped cross-sectional portion and a cone shaped cross-sectional portion.

FIG. 6 is a perspective view of an additional embodiment of a rear derailleur guard assembly adapted for use with a quick-release type rear axle assembly.

FIG. 7 is a cross-sectional view of a portion of the bicycle frame and rear derailleur guard of FIG. 6, taken along the line 7—7 of FIG. 6.

FIG. 8 is a side elevational view of an alternative embodiment of a derailleur guard assembly wherein the body is adjustable relative to an axis of the axle assembly.

FIG. 9 is a side elevational view of an alternative embodiment of a derailleur guard assembly wherein the support is moveable relative to the body of the guard assembly.

FIG. 10 is a side elevational view of an alternative embodiment of a derailleur guard assembly wherein the body comprises a first section and a second section moveable relative to one another to adjust a linear distance between an axis of the axle assembly and the support.

FIG. 11 is a side elevational view of an alternative embodiment of a derailleur guard assembly wherein the support is supported relative to the body by a cam assembly.

FIG. 12 is a side elevational view of an alternative embodiment of a derailleur guard assembly wherein the body includes a first section and a second section moveable relative to one another. The first section and the second section each contact the axle assembly and the support and permit adjustment of a linear distance between an axis of the axle assembly and the support.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 illustrates an off-road bicycle, or mountain bike 20, including one embodiment of a rear derailleur guard assembly. The bicycle 20 is described herein with reference to a coordinate system wherein a longitudinal axis extends from a forward end to a rearward end of the bicycle 20. A vertical, central plane generally bisects the bicycle 20 and contains the longitudinal axis. A lateral axis extends normal to the longitudinal axis and lies within a horizontal plane. In addition, relative heights are generally expressed as elevations from a horizontal surface S upon which the bicycle 20 is supported in an upright position. Similarly, relative forward and rearward positions are expressed as distances from a vertical axis, which is normal to the horizontal surface S. The above-described coordinate system is provided for the convenience of describing the embodiments of FIGS. 1–11, and is not intended to limit the scope of the present invention.

The bicycle 20 includes a frame assembly 22 comprised of a main frame 24 and an articulating frame 26, which is pivotally supported relative to the main frame 24. The bicycle 20 also includes a front wheel 28 carried by a front suspension assembly, or suspension fork 30. The suspension fork 30 is journaled for rotation about a steering axis As defined by the main frame 24. A handlebar assembly 32 is connected to an upper end of the suspension fork 30 and is operable to permit a rider of the bicycle 20 to rotate the front wheel 28 about the steering axis As.

A rear wheel 34 of the bicycle 20 is carried by the articulating frame 26. A shock absorber 36 is pivotally connected between the main frame 24 and the articulating frame 26 to provide resistance to articulating motion of the articulating frame 26 relative to the main frame 24. Thus, the shock absorber 36 is arranged to provide resistance to the suspension travel of the rear wheel 34. A seat assembly 38 is supported above the bicycle frame 22 at a position behind the handlebar assembly 32 and provides support for a rider of the bicycle 20.

A pedal crank assembly 42 is rotatably supported by the bicycle frame 22 and drives a multi-speed chain drive arrangement 44. The multi-speed chain drive arrangement 44 preferably includes a plurality of sprockets, or chain rings 46, coupled for rotation with the pedal crank 42. Typically, three chain rings 46 of varying size are mounted to the pedal crank 42. The chain drive arrangement 44 also includes a plurality of sprockets, or cogs 48, drivingly coupled to the rear wheel 34. A drive chain 50 interconnects a selected chain ring 46 with a selected cog 48 to transfer torque from the pedal crank assembly 42 to the rear wheel 34. Preferably, front and rear derailleurs 52, 54 are supported by the bicycle frame 22 and are configured to move the drive chain 50 to a selected combination of the chain rings 46 and rear cogs 48, respectively.

The bicycle 20 also includes front and rear brake systems 56, 58 configured for slowing and stopping the bicycle 20. Although the illustrated brakes systems 56, 58 are disc-type brakes, other suitable brake systems may also be used, such as rim-type brakes, for example. Rider controls (not shown) are typically provided on the handlebar assembly 32 and are operable to control shifting of the front and rear derailleurs 52, 54 and the front and rear brake systems 56, 58.

With reference to FIGS. 2–5, the rear derailleur guard assembly, referred to generally by the reference numeral 60, is described in greater detail. As described above, preferably the derailleur guard assembly 60 provides support to an outward end of the rear derailleur 54 to reduce the possibility of damage to the derailleur 54, the derailleur mounting bolt or the bicycle frame 22. In addition, preferably, the rear derailleur guard 60 is positioned outwardly from a mounting portion of the rear derailleur 54 to protect the derailleur 54 from damage, as is described in greater detail below.

In the illustrated arrangement, the rear wheel 34 is supported by a through-axle arrangement, wherein an axle assembly 62 includes an axle 64 clamped directly to the frame 22 by a pair of clamp members 66. Rearward ends, or dropouts 68, of a lower portion of the bicycle frame 22 straddle the rear wheel 34. Each of the dropouts 68 define a semi-cylindrical recess 70, which is configured to receive the axle 64. A plurality of bolts 72, each including external threads 74 that mate with internal threads of threaded apertures 76 defined by the dropouts 68, secure the clamp members 66 to the bicycle frame 22. The axle 64 is secured between the recesses 70 of the dropouts 68 and corresponding cylindrical recesses 78 of the clamp members 66.

One of the pair of clamp members 66, typically the right clamp member 66, includes a downwardly extending tab, or derailleur hanger 80. A lower end of the derailleur hanger 80 defines an aperture 82, which includes internal threads. External threads of a derailleur mounting bolt 84 are configured to engage the internal threads of the aperture 82 to secure the mounting bolt 84 to the bicycle frame 22. Desirably, the derailleur mounting bolt 84 also includes a shaft portion, or derailleur supporting portion 86. Preferably, the shaft portion 86 is substantially cylindrical and is sized and shaped to rotatably support the rear derailleur 54 on an outer surface thereof. Desirably, the shaft portion 86 of the derailleur mounting bolt 84 has a lateral dimension, or length along a longitudinal axis of the bolt 84, sufficient to support the rear derailleur 54, as is described in greater detail below.

The derailleur mounting bolt 84 defines a tool engagement surface configured to permit the derailleur mounting bolt 84 to be rotated about its axis by a tool, such as a wrench. In the illustrated embodiment, the tool engagement surface is defined by a tool cavity 88. Preferably, the tool cavity 88 includes a hexagonal-shaped cross-section portion. The tool cavity 88 is configured to receive a correspondingly sized and shaped tool, which permits the mounting bolt 84 to be installed or removed from the derailleur hanger 80.

The derailleur hanger 80 and aperture 82 are configured to support the rear derailleur 54 in an operable position relative to the plurality of cogs 48. As illustrated in FIG. 2, the rear derailleur 54 is typically supported below the cogs 48 and slightly rearward of a hub axis A_(H) defined by the axle 64. As illustrated in FIG. 4, the mounting bolt 84 defines an axis A_(M) about which the rear derailleur 54 is rotatably supported. Desirably, the mounting axis A_(M) is spaced a linear distance D from the hub axis . Preferably, the distance D is between about 24 millimeters and 34 millimeters. Commonly, the distance D is between about 28–30 millimeters for a mountain bike frame, such as the frame 22, and between about 26–28 millimeters for a road bicycle frame. However, the derailleur guard 60 may be configured for use with bicycle frames having a distance D of other values as well.

The rear derailleur 54 includes a mounting portion 90 and a movable portion, or cage 92, interconnected by a connecting portion 94. The mounting portion 90 defines a cylindrical aperture 96 near its uppermost end, which permits the derailleur 54 to be supported by the shaft portion 86 of the derailleur mounting bolt 84. The mounting portion 90 of the derailleur 54 is permitted to pivot about the derailleur mounting axis A_(M).

The derailleur cage 92 rotatably supports an upper pulley 100 and a lower pulley 102. Each of the upper and lower pulleys 100, 102 include a plurality of gear teeth thereon, which engage the drive chain 50. The derailleur cage 92 is movable relative to the mounting portion 90, substantially parallel to the axis A_(M), to move the drive chain 50 to a selected one of the plurality of cogs 48. As in known in the art, the derailleur 54 preferably includes a spring (not shown) which is configured to bias the derailleur cage 92 in one direction relative to the mounting portion 90. Typically, the spring biases the derailleur cage 92 toward the smaller cogs 48 or outwardly relative to the bicycle frame 22. A cable, or bowden wire, (not shown) typically interconnects a shifting mechanism located on the handlebar assembly 32 (FIG. 1) with the rear derailleur 54 and is operable to apply tension to the cable to overcome the resistance force provided by the spring. Thus, tension applied to the cable tends to move the derailleur cage 92 toward the larger cogs 48 or inwardly relative to the bicycle frame 22, toward a center plane C_(p) (FIG. 4) of the bicycle 20.

In addition to moving the chain between the cogs 48, the rear derailleur 54 also operates to apply tension to the drive chain 50 and thereby absorb slack within the chain 50. Because the drive chain 50 is a continuous loop, as the chain 50 moves to smaller cogs 48 or smaller chain rings 46 (FIG. 1) the slack in the chain 50 increases, while the slack is decreased when the chain 50 moves to larger cogs 48 or larger chain rings 46. To absorb or release slack within the drive chain 50, the derailleur cage 92 is biased in a clockwise direction relative to the remainder of the derailleur 54, as illustrated by the arrow A in FIG. 2. Typically, a torsion spring element (not shown) is provided to bias the derailleur cage 92 in the direction of the arrow A. As described above, the greater the difference between the smallest gear ratio (i.e., the combination of the smallest chain ring 46 and the smallest cog 48) and the largest gear ratio (i.e., the largest chain ring 46 and the largest cog 48), the greater the amount of slack produced when the chain 50 is interconnecting small chain rings 46 and cogs 48. Due to the relatively large variation in the slope of the terrain to which a mountain bike is subjected, the difference between the smallest gear ratio and the largest gear ratio is typically substantially greater than a bicycle intended for use primarily on the road. As a result, a mountain bike drive chain produces a relatively large amount of slack in the chain when in smaller gear ratios.

The amount of slack capable of being absorbed by the rear derailleur 54 is influenced at least in part by a distance L between the axes of rotation of the upper pulley 100 and the lower pulley 102, or a length of the derailleur cage 92. Thus, to absorb the large amount of slack produced in the chain 50 of a mountain bike drive train, a mountain bike rear derailleur 54 is typically provided with a relatively long derailleur cage 92. As a result, a lower end of the derailleur cage 92 extends a significant distance below the hub axis A_(h), where it is highly susceptible to being struck by objects (e.g., rocks or sticks) encountered while riding or striking the ground in the event of a crash.

In the absence of a derailleur guard 60, the derailleur hanger 80 is prone to bending, or other damage, when the derailleur 54 is forcefully struck by an object. In fact, a substantial percentage of bicycle frames are provided with replaceable derailleur hangers 80, due to the relatively common occurrence of damage to the derailleur hanger 80. Furthermore, the thickness of the derailleur hanger 80 is limited because, to be capable of guiding the chain 50 onto each of the cogs 48, the derailleur cage 92 must be capable of being aligned with each cog 48. The innermost cog 48 is typically located a substantial distance inward from the derailleur hanger 80. Accordingly, increasing the thickness of the derailleur hanger 80 to increase its strength is likely to prevent the derailleur 54 from being able to move the drive chain 50 to the innermost cogs 48.

Other failure modes resulting from forceful impacts to the derailleur 54 include breaking of the derailleur mounting bolt 84 or failure of the derailleur hanger 80 fasteners, in the situation of a replaceable hanger 80, as described immediately above. In either situation, if the failure of the bolt 84, or hanger 80 fasteners, is complete, the derailleur 54 is separated from the bicycle frame 22 and is no longer capable of shifting the chain 50 and, in some cases, may render the bicycle 20 unrideable. Even if the failure of the bolt 84, or hanger 80 fasteners, is not complete, the derailleur 54 may not be sufficiently supported to maintain alignment with the cogs 48.

The illustrated rear derailleur guard 60 is configured to provide support to the rear derailleur 54 and inhibit damage to the derailleur hanger 80, or mounting bolt 84, in the event of the derailleur 54 being forcefully struck by an object. Preferably, the rear derailleur guard assembly 60 includes a body portion 110 supported relative to the bicycle frame 22 by the axle 64. However, the body 110 may also be supported by other components of the bicycle 20, such as the frame 22 itself. In the illustrated embodiment, the axle 64 includes an extension portion 112, which extends outwardly from an outer surface 114 of the right dropout 68 of the bicycle frame 22. In the illustrated arrangement, the axle 64 and the extension 112 are unitary, or formed from a single piece of material. However, in alternative arrangements the extension 112 may be otherwise coupled to the axle 64, such as through mechanical fastening means for example.

Desirably, the extension 112 is substantially cylindrical in shape, with the exception of a pair of opposed, planar surfaces, or flats 116. The body 110 of the guard assembly 60 includes a mounting aperture 118 sized and shaped to receive the extension 112 therewithin. Thus, the mounting aperture 118 includes a pair of opposed flats 120 which contact the flats 116 of the extension 112 to prevent rotation of the body 110 relative to the axle 64. That is, the flats 116, 120 provide a “keyed” connection between the body 110 and the axle 64.

The body 110 of the guard assembly 60 desirably extends below the axle 64 to a space adjacent the mounting portion 90 of the rear derailleur 54. As described above, the distance D between the hub axis A_(H) and the mounting axis A_(M)may vary. Preferably, the length of the illustrated body 110 is configured to accommodate the distance D of the specific bicycle frame 22 on which the guard assembly 60 is intended for use. Preferably, the body 110 does not extend significantly below the mounting portion 90 of the derailleur and, more preferably, does not extend significantly below the mounting bolt 86 of the derailleur 54. In addition, preferably, the body 110 does not extend to a forward side of the derailleur 54 because the derailleur 54 tends to swing in a forward direction when the bicycle 20 traverses rough terrain. Accordingly, the body 110 illustrated in FIGS. 1–4 does not interfere with such movement of the derailleur 54, which would cause undesirable noise and may damage the derailleur.

The body 110 defines an inner surface 122, which faces the outer surface 114 defined by the dropout 68 of the bicycle frame 22. In the illustrated embodiment, a lower end portion of the inner surface 122 of the body 110 defines a recess 124. The recess 124 preferably is sized and shaped to accommodate a portion of the mounting portion 90 of the rear derailleur 54. Desirably, the inner surface 122 of the recess 124 is in relatively close proximity to the outer surface of the mounting bolt 84. Accordingly, a lower end of the body 110 is positioned outwardly of the mounting bolt 84, and upper most end of the mounting portion 90. Thus, the body 110 is advantageously positioned to absorb impacts from a side direction of the bicycle 20. Accordingly, damage to the mounting bolt 84 or mounting portion 90 of the rear derailleur 54 is substantially inhibited or prevented.

A lower end of the body 110 adjacent the mounting bolt 84 desirably includes a cylindrical aperture 126, which is configured to receive a support 128. Preferably, the support 128 includes a substantially cylindrical end 130 and a hexagonal-shaped cross section end 132 connected by a tapered, or partial cone-shaped portion 134 (FIG. 4). Desirably, a lateral width of the portion of the body 110 defining the aperture 126 is at least about 5 millimeters. Preferably, the width is about 5 millimeters for a guard body 110 constructed of aluminum. Such a width provides a desirable level of support to the cylindrical end 130 of the support 128. In addition, such a construction provides a desirable level of strength to absorb forceful impacts and minimize or substantially eliminate damage to the derailleur 54, mounting bolt 84, or derailleur hanger 80.

Preferably, the body 110 includes a slot 136 extending between the mounting aperture 118 and the support aperture 126. Desirably, a bolt 140 is supported by an aperture defined by the body 110 and extends through the slot 136 in a direction substantially perpendicular to the length of the slot 136. The bolt 140 includes a threaded end portion having external threads that mate with internal threads of the aperture defined by the body 110. Thus, the bolt 140 interconnects opposing portions of the body 110 separated by the slot 136 and may be used to increase or decrease a width of the slot 136, thereby increasing or decreasing a size of the apertures 118, 126 simultaneously. Accordingly, the bolt 140 may be tightened to reduce the size of the aperture 118, which develops a clamping force to secure the body 110 to the extension 112. As described above, the corresponding flats 116, 120 of the extension 112 and the aperture 118 of the guard body 110 inhibit rotation of the body 110 relative to the axle 64. In addition, the clamp force generated by the bolt 140 also reduces the size of the aperture 126 to apply a clamping force to the cylindrical portion 130 of the support 128 and prevent rotation of the support 128 relative to the body 110.

Preferably, the hexagonal-shaped portion 132 of the support 128 is sized and shaped to be received by the hexagonal-shaped portion of the tool cavity 88 defined by the derailleur mounting bolt 84. Desirably, the hexagonal-shaped portion 132 extends substantially the entire length of the hexagonal-shaped portion of the tool cavity 88. In addition, desirably the tapered portion 134 of the support 128 is configured to contact an outward portion of the tool cavity 88, as is described in greater detail below with reference to FIG. 5. Alternatively, the hexagonal-shaped end 132 of the support 128 may be omitted and the tool cavity 88 may be contacted only by a tapered portion 134 of the support 128.

With the illustrated construction, the support 128 and the mounting bolt 84 cooperate to form a support beam for the rear derailleur 54. The beam created by the support 128 and mounting bolt 84 is rigidly supported at an inward end by the derailleur hanger 80 and at an outward end by the body 110 of the guard assembly 60. Thus, preferably both ends of the beam are prevented from moving in any direction. With such a construction, advantageously, the mounting portion 90 of the rear derailleur 54 is supported from both its inward facing and outward facing ends. Thus, when the derailleur guard assembly 60 is installed, the rear derailleur 54 is no longer supported solely by the derailleur hanger 80 and mounting bolt 84 in a cantilevered arrangement, but is supported in addition by the body 110 and support 128.

In operation, the derailleur 54 is mounted to the derailleur hanger 80 by the mounting bolt 84. The support 128 may be positioned such that the hexagonal-shaped portion 132 is received within the hexagonal tool cavity 88 of the mounting bolt 84. The body 110 may then be positioned such that the extension 112 of the axle 64 is received within the aperture 118 and the cylindrical portion 130 of the support is received within the aperture 126. Advantageously, the body 110 may be moveable along the extension 112 relative to the hub axis A_(H) in order to compensate for varying thickness of the dropouts 68, derailleur 54 widths or other component variations among different manufacturers, or even normal manufacturing tolerances. Once the body 110 is properly position, the bolt 140 may be tightened to secure the body 110 to the axle 64 and secure the support 128 to the body 110, as described above.

Furthermore, the entire guard assembly 60 is easily removable from the bicycle 20 to accommodate removal of the rear wheel 34, as is a relatively frequent occurrence in mountain biking. Removal of the rear wheel 34 may be necessary while on the trail, where a minimum of tools are typically available. Therefore, it is highly advantageous for any derailleur guard 60 incorporated on the bicycle 20 to be easily removable. The illustrated guard assembly 60 may be removed by loosening the bolt 140 and moving the body 110 axially away from the derailleur 54 to disengage the support 128 from the derailleur mounting bolt 84. Thus, preferably, the guard 60 is removable with the loosening of one bolt. Alternatively, the body 110 may remain fixed to the axle 64, which may be removed from the bicycle 20 by removing the axle clamps 66. The axle 64 may then be moved toward the derailleur 54 side of the bicycle 20 to similarly disengage the support 128 from the derailleur mounting bolt 84.

FIG. 5 is an enlarged, partial cross-section view of the derailleur guard support 128 illustrated in an engaged position relative to the derailleur mounting bolt 84. As illustrated, the tool cavity 88 is divided into an innermost section 150 and an outermost section 152. Preferably, the innermost section 150 is hexagonal-shaped in cross-section, while the outermost section 152 is substantially cylindrical in shape and, typically, larger than the innermost section 150. Accordingly, the hexagonal portion 132 of the support 128 engages section 150 of the tool cavity 88, while an annular portion of the section 152 contacts the tapered portion 134 of the support 128. Accordingly, the derailleur mounting bolt 84 is supported along a substantial portion of its length by the support 128. In an alternative arrangement, as described above, the hexagonal section 150 of the support 128 may be omitted and the support 128 may comprise only a tapered section. Furthermore, other derailleur mounting bolts may include a tool cavity only having a hexagonal portion extending inwardly from the outer surface of the mounting bolt. Accordingly, the support 128 may be provided with only the hexagonal portion 132 to correspond with such a tool cavity. In addition, the support 128 may be otherwise modified to correspond with the shape of an alternative tool engagement surface of a derailleur mounting bolt.

FIGS. 6 and 7 illustrate an additional embodiment of a derailleur guard assembly, referred to generally by the reference numeral 200. The rear derailleur guard 200 is similar to the derailleur guard 60 of FIGS. 1–4, except that the derailleur guard 200 is configured for use with a quick-release type axle assembly. However, desirably, the derailleur guard 200 provides substantially the same advantages as the derailleur guard 60.

FIG. 6 is an enlarged, perspective view of a rearward end of a bicycle frame 202. The bicycle frame 202 defines a pair of dropouts 204, which straddle a rear wheel (not shown) supported by the frame 202. Each dropout 204 includes a slot 206 extending generally in a vertical direction from a lower surface of the dropout 204. The slots 206 are configured to receive an axle 208, which typically extends no further than outward facing surfaces of the dropouts 204. The axle 208 is configured to support the rear wheel and plurality of cogs (not shown) in a manner similar to the axle 64 of FIGS. 1–4.

However, the axle 208 is not clamped directly to the bicycle frame 202. Instead, a quick release assembly 210 couples the axle 208 to the bicycle frame 202. Typically, the quick-release assembly 210 includes an elongated rod, or skewer 212 that passes through the hollow axle 208 and extends beyond the outward facing surfaces of the dropouts 204. A first end of the skewer includes a cam and lever arrangement 214 and the second end of the skewer 212 includes an adjusting nut 216. The lever and cam arrangement 214 is configured to selectively apply a squeezing force on the dropouts 204 to secure the axle 208 and the rear wheel to the frame 202.

In addition, the right dropout 204 preferably includes a derailleur hanger 218, which is configured to receive a derailleur mounting bolt 220. The derailleur mounting bolt 220 supports a rear derailleur 222 and an operable position relative to the bicycle frame 202 and the rear wheel carried by the axle 208. Preferably, the derailleur 222 is substantially similar in construction and operation to the derailleur 54 described in connection with FIGS. 1–4.

Because the axle 208 does not extend beyond an outward facing surface 224 of the dropout 204, the derailleur guard assembly 200 includes a guard block 226. Desirably, the guard block 226 includes a center aperture 228 that permits the guard block 226 to be carried by the skewer 212. To accommodate the guard block 226, the skewer 212 may be longer than a typical skewer used on a bicycle that does not incorporate the guard assembly 200.

Preferably, at least an outer end of the guard block 226 is configured to support the body 232. Desirably, the shape of the guard block 226 is substantially similar to the shape of the extension 112 of the axle 64 of FIGS. 1–4. Accordingly, preferably the guard block 226 includes a pair of opposed flats 230 to prevent rotation of the guard body 232 relative to the guard block 226 in a manner substantially similar to that described above with respect to the guard assembly 60. Desirably, a clamping force exerted by the quick-release assembly 210 inhibits the guard block 226 from rotating relative to the axle 208.

In addition, preferably, the guard assembly 200 includes a support 234, which cooperates with the mounting bolt 220 to support the rear derailleur 222 in a manner substantially similar to that described above with respect to the guard assembly 60 of FIGS. 1–4. Preferably, a bolt 236 is operable to clamp the body 232 to the guard block 226 and secure the support 134 to the body 232, substantially as described above in connection with the guard assembly 60 of FIGS. 1–4.

FIG. 8 is a side, elevational view of an alternative embodiment of a guard body, generally referred to by the reference numeral 250. Desirably, the guard body 250 is substantially similar to the guard bodies 110 of FIGS. 1–4 and 232 of FIGS. 6 and 7, except that the body 250 permits adjustment of the distance D between the hub axis A_(h) and the mounting axis A_(m) of the previously-described supports 128 or 234.

Preferably, the guard body 250 includes an aperture 252 that is elongated along the length of the body 250. Desirably, opposing side surfaces of the aperture 252 are generally planar and spaced to accommodate the flat surfaces 116 of the axle extension 112 (FIG. 3). The body 250 may be moved up or down relative to the hub axis A_(h) as indicated by the arrow 254 of FIG. 8. Accordingly, the guard body 250 permits an associated derailleur guard assembly to be used on a variety of bicycle frames, in which the distance D may vary among the different frames.

FIG. 9 is an illustration of another alternative embodiment of a guard body, generally referred to by the reference numeral 260. The guard body 260 includes an elongated slot 262, which is configured to receive a support 128 or 234. The elongated slot 262 permits the support to be moved in an upward or downward direction relative to the body 260, as illustrated by the arrow 264, to adjust a distance D between the hub axis A_(h) and the mounting axis A_(m).

FIG. 10 illustrates yet another embodiment of a guard body, referred to generally by the reference numeral 270. Preferably, the body 270 includes a first section 272 and a second section 274. The first section 272 includes an aperture 276 configured to receive the axle extension 112. The second section 274 includes an aperture 278 configured to receive a support 128 or 234. The first and second section are coupled, preferably by a pair of bolts 280 passing through the second section 274 and threadably engaged with the first section 272. Desirably, the second section includes a pair of vertically oriented, elongated apertures 282 through which the bolts 280 pass. Thus, the second section 274 may be moved upward and downward relative to the first section 272, as illustrated by the arrow 284, to adjust a distance D between the hub axis A_(h), and the mounting axis A_(m).

FIG. 11 illustrates another alternative embodiment of a guard body, generally referred to by the reference numeral 290. The guard 290 includes a cam arrangement 292, which supports a support 128 or 234 within an aperture 293 relative to the guard body 290. The cam arrangement 292 supports the support 128, 234 off-center from a center of the aperture 293. Thus, rotation of the cam assembly 292 permits the distance D to be adjusted. In addition, an upper aperture 294 of the guard body 290 may include a cam arrangement to support the guard body 290 relative to the axle extension 112, or guard block 226. Accordingly, such a cam assembly within the aperture 294 would permit additional adjustment of the distance D.

FIG. 12 illustrates yet another embodiment of a guard body, generally referred to by the reference numeral 300. The body 300 is vertically divided into a first section 302 and a second section 304 configured to be connectable to one another. Preferably, the sections 302, 304 are coupled by a pair of bolts 306 passing through a pair of elongated apertures 307. The apertures 307 permit vertical, relative movement between the first and second sections 302, 304, as illustrated by the arrows 309 of FIG. 12. The first and second sections 302, 304 are configured to receive the extension 112, or guard block 226, and the support 128, 234 therebetween.

Desirably, an upper end 308 of the first section 302 and a lower end of the second section 304 are elongated. Preferably, the ends 308, 310 define elongated flat surfaces 312, 314, respectively, which face inwardly. An upper end 316 of the first section 302 faces the flat surface 312 of the second section 304. A lower end 318 of the second section 304 faces the flat surfaces 314 of the first section 302. The ends 316, 318 include recesses 320, 322, respectively. The recess 320 is configured to support the extension 112, or guard block 226, in a generally fixed position relative to the second section 304. Similarly, the recess 322 is configured to support the support 128, 234 in a generally fixed position relative to the first section 302. Thus, the first section 302 and the second section 304 may be adjusted relative to one another to adjust the distance D between the hub axis A_(h) and the mounting axis A_(m).

Although the present invention has been disclosed in the context of several preferred embodiments, it will be understood by those of skill in the art that the scope of the present invention extends beyond the specifically disclosed embodiments to alternative embodiments and obvious modifications and equivalence thereof. For example, although a number of embodiments of preferred derailleur guard assemblies have been described herein, it is not intended to limit the present invention to any one of the illustrated embodiments. Accordingly, the invention is intended to be defined solely by the appended claims. 

1. A bicycle rear derailleur guard assembly for use with a bicycle having a derailleur mounted to a frame of the bicycle by a derailleur mounting bolt defining a tool cavity, said derailleur guard assembly comprising: a body supportable by an axle assembly of the bicycle, said body being configured to extend from an axis of the axle assembly to a space adjacent the derailleur mounting bolt and defining an inner surface facing the frame when said derailleur guard assembly is mounted to the bicycle; a support extending from said inner surface, said support being configured to engage the tool cavity of the derailleur mounting bolt when said derailleur guard assembly is mounted to the bicycle; wherein said support and the derailleur mounting bolt cooperate to create a support beam for the derailleur, said support beam being rigidly supported by the frame at a first end and rigidly supported by the body at a second end; and wherein said support comprises a hexagonal-shaped cross-section configured to cooperate with a hexagonal-shaped cross-section of the tool cavity.
 2. A bicycle rear derailleur guard assembly for use with a bicycle having a derailleur mounted to a frame of the bicycle by a derailleur mounting bolt defining a tool cavity, said derailleur guard assembly comprising: a body supportable by an axle assembly of the bicycle, said body being configured to extend from an axis of the axle assembly to a space adjacent the derailleur mounting bolt and defining an inner surface facing the frame when said derailleur guard assembly it mounted to the bicycle; a support extending from said inner surface, said support being configured to engage the tool cavity of the derailleur mounting bolt when said derailleur guard assembly is mounted to the bicycle, wherein the tool cavity is configured to receive a correspondingly sized and shaped tool; wherein said support and the derailleur mounting bolt cooperate to create a support beam for the derailleur, said support beam being rigidly supported by the frame at a first end and rigidly supported by the body at a second end and wherein said support comprises a tapered cross-section.
 3. A bicycle rear derailleur guard assembly for use with a bicycle having a derailleur mounted to a frame of the bicycle by a derailleur mounting bolt defining a tool cavity, said derailleur guard assembly comprising: a body supportable by an axle assembly of the bicycle, said body being configured to extend from an axis of the axle assembly to a space adjacent the derailleur mounting bolt and defining an inner surface facing the frame when said derailleur guard assembly is mounted to the bicycle; a support extending from said inner surface, said support being configured to engage the tool cavity of the derailleur mounting bolt when said derailleur guard assembly is mounted to the bicycle; wherein said support and the derailleur mounting bolt cooperate to create a support beam for the derailleur, said support beam being rigidly supported by the frame at a first end and rigidly supported by the body at a second end; and wherein said support comprises both a hexagonal-shaped cross-section portion configured to cooperate with a hexagonal-shaped cross-section portion of the tool cavity and a tapered cross-section configured to contact a portion of the tool cavity having a greater cross-sectional dimension than the hexagonal-shaped cross-section portion.
 4. A bicycle rear derailleur guard assembly for use with a bicycle having a derailleur mounted to a frame of the bicycle by a derailleur mounting bolt defining a tool cavity, said derailleur guard assembly comprising: a body supportable by an axle assembly of the bicycle, said body being configured to extend from an axis of the axle assembly to a space adjacent the derailleur mounting bolt and defining an inner surface facing the frame when said derailleur guard assembly is mounted to the bicycle; a support extending from said inner surface, said support being configured to engage the tool cavity of the derailleur mounting bolt when said derailleur guard assembly is mounted to the bicycle; wherein said support and the derailleur mounting bolt cooperate to create a support beam for the derailleur, said support beam being rigidly supported by the frame at a first end and rigidly supported by the body at a second end; and wherein said body is supported by the axle assembly of the bicycle, said body being keyed to the axle to prevent rotation therebetween.
 5. The guard assembly of claim 4, wherein the axle assembly is supported by a dropout of the bicycle frame, the axle assembly comprising an axle defining an extension protruding beyond an outer surface of the dropout, said body being supported by the extension.
 6. The guard assembly of claim 4, wherein the axle assembly comprises a quick-release assembly, said guard assembly additionally comprising a guard block securable relative to the bicycle frame by the quick-release assembly, said guard block being configured to support said body.
 7. A bicycle rear derailleur guard assembly for use with a bicycle having a derailleur mounted to a frame of the bicycle by a derailleur mounting bolt defining a tool cavity, said derailleur guard assembly comprising: a body supportable by an axle assembly of the bicycle, said body being configured to extend from an axis of the axle assembly to a space adjacent the derailleur mounting bolt and defining an inner surface facing the frame when said derailleur guard assembly is mounted to the bicycle; a support extending from said inner surface, said support being configured to engage the tool cavity of the derailleur mounting bolt when said derailleur guard assembly is mounted to the bicycle, wherein the tool cavity is configured to receive a correspondingly sized and shaped tool; wherein said support and the derailleur mounting bolt cooperate to create a support beam for the derailleur, said support beam being rigidly supported by the frame at a first end and rigidly supported by the body at a second end; and wherein said body comprises a first aperture configured to receive the axle assembly and a second aperture configured to receive said support, said body additionally comprising a slot extending between the first and second aperture, said guard assembly additionally comprising a clamp arrangement configured to reduce a width of said slot, thereby reducing a size of said first and second apertures and clamping said body to the axle assembly and said support, respectively.
 8. A bicycle rear derailleur guard assembly for use with a bicycle having a derailleur mounted to a frame of the bicycle by a derailleur mounting bolt defining a tool cavity, said derailleur guard assembly comprising: a body supportable relative to an axis of an axle assembly of the bicycle, said body being configured to extend to a space adjacent the derailleur mounting bolt and defining an inner surface facing the frame when said derailleur guard assembly is mounted to the bicycle; a support extending from said inner surface, said support being at least indirectly supported by said derailleur mounting bolt to support the derailleur when said derailleur guard assembly is mounted to the bicycle; wherein a linear distance between said support and the axis of the axle assembly when said derailleur guard is mounted on the bicycle is adjustable.
 9. The guard assembly of claim 8, wherein said body is movable relative to the axis of the axle assembly.
 10. The guard assembly of claim 8, wherein said support is movable relative to said body.
 11. The guard assembly of claim 8, wherein said body comprises a first section and a second section, said first section and said second section being movable relative to one another and each of said first section and said second section contacting the axle assembly and said support.
 12. The guard assembly of claim 8, wherein said body comprises a first section and a second section, said first section and said second section being movable relative to one another and said first section being supported by the axle assembly and said second section supporting said support.
 13. The guard assembly of claim 8, wherein said body is supported relative to the axis of the axle assembly by a cam arrangement.
 14. The guard assembly of claim 8, wherein said support is supported relative to said body by a cam arrangement.
 15. A bicycle rear derailleur guard assembly for use with a bicycle having a derailleur mounted to a frame of the bicycle by a derailleur mounting bolt, said derailleur guard assembly comprising: a body supportable by an axle assembly of the bicycle, said body being configured to extend from an axis of the axle assembly to a space adjacent the mounting bolt of the derailleur and defining an inner surface facing the frame when said guard assembly is mounted to the bicycle; a support held by said body, said support being configured to support the derailleur when said guard assembly is mounted to the bicycle; wherein said body is positioned outwardly of the derailleur mounting bait within said space adjacent said mounting bolt; and wherein said support comprises a hexagonal-shaped cross-section configured to cooperate with a hexagonal-shaped cross-section of the tool cavity.
 16. A bicycle rear derailleur guard assembly for use with a bicycle having a derailleur mounted to a frame of the bicycle by a derailleur mounting bolt, said derailleur guard assembly comprising: a body supportable by an axle assembly of the bicycle, said body being configured to extend from an axis of the axle assembly to a space adjacent the mounting bolt of the derailleur and defining an inner surface facing the frame when said guard assembly is mounted to the bicycle; a support held by said body, said support being configured to support the derailleur when said guard assembly is mounted to the bicycle; wherein said body is spaced outwardly from an outermost end of said mounting bolt along an axis of said mounting bolt and wherein said support comprises a tapered cross-section.
 17. The guard assembly of claim 16, wherein said support comprises a hexagonal-shaped cross-section portion configured to cooperate with a hexagonal-shaped cross-section portion of the tool cavity and wherein said tapered cross-section is configured to contact a portion of the tool cavity having a greater cross-sectional dimension than the hexagonal-shaped cross-section portion.
 18. A bicycle rear derailleur guard assembly for use with a bicycle having a derailleur mounted to a frame of the bicycle by a derailleur mounting bolt, said derailleur guard assembly comprising: a body supportable by an axle assembly of the bicycle, said body being configured to extend from an axis of the axle assembly to a space adjacent the mounting bolt of the derailleur and defining an inner surface facing the frame when said guard assembly is mounted to the bicycle; a support held by said body, said support being configured to support the derailleur when said guard assembly is mounted to the bicycle; wherein said body is spaced outwardly from an outermost end of said mounting bolt along an axis of said mounting bolt and wherein said body is supported by the axle assembly of the bicycle, said body being keyed to the axle to prevent rotation therebetween.
 19. The guard assembly of claim 18, wherein the axle assembly is supported by a dropout of the bicycle frame, the axle assembly comprising an axle defining an extension protruding beyond an outer surface of the dropout, said body being supported by the extension.
 20. The guard assembly of claim 18, wherein the axle assembly comprises a quick-release assembly, said guard assembly additionally comprising a guard block securable relative to the bicycle frame by the quick-release assembly, said guard block being configured to support said body.
 21. A bicycle rear derailleur guard assembly for use with a bicycle having a derailleur mounted to a frame of the bicycle by a derailleur mounting bolt, said derailleur guard assembly comprising: a body supportable by an axle assembly of the bicycle, said body being configured to extend from an axis of the axle assembly to a space adjacent the mounting bolt of the derailleur and defining an inner surface facing the frame when said guard assembly is mounted to the bicycle; a support held by said body, said support being configured to support the derailleur when said guard assembly is mounted to the bicycle; wherein said body is spaced outwardly from an outermost end of said mounting bolt along an axis of said mounting bolt; and wherein said body comprises a first aperture configured to receive the axle assembly and a second aperture configured to receive said support, said body additionally comprising a slot extending between the first and second aperture, said guard assembly additionally comprising a clamp arrangement configured to reduce a width of said slot, thereby reducing a size of said first and second apertures and clamping said body to the axle assembly and said support, respectively. 